The makers of mobile communication devices such as cellular telephones continue to increase functionality of these devices. For example, at present cellular telephones can include still and video cameras, video streaming and/or two-way video calling capabilities. Users can capture still or video images and transmit the image or video files via a network. While the trend to increase functionality continues, manufacturers also continue to reduce the size of such communication devices.
The reduced size of such mobile communication devices have restricted the use of diaphragms with adjustable apertures or irises in the cameras contained therein. A mechanical camera iris is a diaphragm having a variable opening for a camera lens to alter the amount of light being admitted as well as to adjust the depth of field available for the image. Such mechanical irises are utilized in most film cameras and in many digital cameras. A mechanical iris is not practical for use in mobile communication devices because it would add too much bulk, increased costs, and may have unreliable performance. Thus, manufacturers typically do not include adjustable irises in cellular telephones. The consequence is that cellular telephones neither produce good quality images at low light levels (due to, for example, objectionable shot noise and readout noise) nor at high light levels due, for example, to the inability to adequately decrease integration times thereby creating over-saturation problems. Cellular telephone cameras also can exhibit poor depth of field and reduced image sharpness due to lens aberration.